Are tachoclines important for solar and stellar dynamos? What can we learn from global simulations
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Universidade Federal de Minas Gerais
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Artigo de periódico
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Membros da banca
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The role of tachoclines, the thin shear layers that separate solid body from differential rotation in the interior of late-type stars, in stellar dynamos is still controversial. In this work we discuss their relevance in view of recent results from global dynamo simulations performed with the EULAG-MHD code. The models have solar-like stratification and different rotation rates (i.e., different Rossby number). Three arguments supporting the key role of tachoclines are presented: the solar dynamo cycle period, the origin of torsional oscillations and the scaling law of stellar magnetic fields as function of the Rossby number. This scaling shows a regime where the field strength increases with the rotation and a saturated regime for fast rotating stars. These properties are better reproduced by models that consider the convection zone and a fraction of the radiative core, naturally developing a tachocline, than by those that consider only the convection zone.
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Stars, Rotation
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https://www.cambridge.org/core/journals/proceedings-of-the-international-astronomical-union/article/are-tachoclines-important-for-solar-and-stellar-dynamos-what-can-we-learn-from-global-simulations/E7627CA42D7B5418141883E958CECDB8